From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B7F3C43215 for ; Sat, 16 Nov 2019 16:09:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0AD852089D for ; Sat, 16 Nov 2019 16:09:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573920579; bh=PZrL9vWqCTiFw2xV4xCtIutuGc0aIhE7zE1PDg4v3/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aPVTpAGhFSazbE9a8gUM8o9Dv/IwUj06j+9i6gphRyHEYc6ZGvBLKLmVEc2MvNXL8 23gD7G4wv2uZg3AfDF4BAQFL1YktFF/Z3fIcFXlDb/x4E9dBGM6C+JyFHiieDWCZOD h8LeBvHp0IMolj8HGQj0BSkGHCs4pmHHvFICqYHo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727993AbfKPPtf (ORCPT ); Sat, 16 Nov 2019 10:49:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:57040 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730320AbfKPPt0 (ORCPT ); Sat, 16 Nov 2019 10:49:26 -0500 Received: from sasha-vm.mshome.net (unknown [50.234.116.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6A93020870; Sat, 16 Nov 2019 15:49:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919365; bh=PZrL9vWqCTiFw2xV4xCtIutuGc0aIhE7zE1PDg4v3/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V6PlZZqPcDvDOiHGjIkG32U1y3ENQJy61urFVoYSC2juGfZ6AFu0g5rF1MtgaocKN B92O05DB69DTfpetnmcGg9oS9fX3dhMDobdmVqugzmhvazuJTj4zN0qwoXT6+sr3Ut YsNxHu0U2l4+xVhwfpbtNvIBTNzUa956S/aQH8Vc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Anton Ivanov , Richard Weinberger , Sasha Levin , linux-um@lists.infradead.org Subject: [PATCH AUTOSEL 4.14 087/150] um: Make line/tty semantics use true write IRQ Date: Sat, 16 Nov 2019 10:46:25 -0500 Message-Id: <20191116154729.9573-87-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191116154729.9573-1-sashal@kernel.org> References: <20191116154729.9573-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Anton Ivanov [ Upstream commit 917e2fd2c53eb3c4162f5397555cbd394390d4bc ] This fixes a long standing bug where large amounts of output could freeze the tty (most commonly seen on stdio console). While the bug has always been there it became more pronounced after moving to the new interrupt controller. The line semantics are now changed to have true IRQ write semantics which should further improve the tty/line subsystem stability and performance Signed-off-by: Anton Ivanov Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin --- arch/um/drivers/line.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c index 366e57f5e8d63..7e524efed5848 100644 --- a/arch/um/drivers/line.c +++ b/arch/um/drivers/line.c @@ -261,7 +261,7 @@ static irqreturn_t line_write_interrupt(int irq, void *data) if (err == 0) { spin_unlock(&line->lock); return IRQ_NONE; - } else if (err < 0) { + } else if ((err < 0) && (err != -EAGAIN)) { line->head = line->buffer; line->tail = line->buffer; } -- 2.20.1